Medical implants often comprise two components which are difficult to reliably connect to one another at reasonable cost. For example, elements made of NiTinol (metal alloy of nickel and titanium) may only be machined with difficulty. NiTinol workpieces may for example extremely difficult be provided with bores or threads. This applies particularly to components which have bundles of strands. Moreover, elements made of NiTinol cannot be connected to elements made of other metals virtually at all by soldering or welding, since such connections are at least not permanently durable and therefore do not satisfy the requirements to be fulfilled by medical implants. Such connections can therefore be implemented only with difficulty.
One possibility is to push a clamp over a bundle of strands and clamp this clamp together with the bundle of strands, as is known, for example, in the case of cable ends.
However, such clamping of a per se flexible bundle of wires or strands may not reliably provide long-term fixation of the clamp to the bundle. The clamp may loosen. The clamp may also affect the strands and affect strength of the strands' material.
Clamps for clamping bundles of strands of a tubular braided metal fabric at two ends of a medical device is disclosed in WO99/12478. The bundles are prevented from unraveling by means of one clamp at each end of the device. Each clamp is clamping together a distal and a proximal bundle of strands of the tubular fabric. The clamps are clamped to the bundle after cutting of the latter to a desired length. One of the clamps comprises an internal thread for attachment of the device to a guidewire during delivery. Clamping of a tubular fabric, in particular a braided tubular fabric, may prove difficult to achieve before the fabric unravels.
Alternatively, it is disclosed in WO99/12478 that the ends may be welded. However, by welding the ends together, it becomes difficult to attach a delivery device to one of the ends as welded clots of strands are not directly provideable with a thread. Welded ends tend to also to be irregular in shape as the liquefied metal strands flow away before cooling down and becoming solidified again. This affects quality of the manufacturing process contrary to the high quality requirements of medical devices.
Moreover, the type of clamped connection disclosed in WO99/12478 is also not permanently reliable, as explained above. For example when the medical implant is constantly exposed to loads and deformations in the body, such as, for example, in the heart, structural weaknesses may occur due to the clamp.
Hence, a reliable permanent connection of an element to a bundle of strands is needed.
Similar issues apply when connection of the bundle to other elements is to be made in a reliable way for temporary connections, e.g. during delivery of the medical implant.
Another issue is reduction of cost of manufacture of such medical implants having permanent or temporary connections of bundles to other elements. For instance it is desired to minimize manual handling steps.
The connection of the elements may be temporary or permanently arranged. Positive or non-positive connection of the elements to the bundle of strands is facilitated. The different elements affixed to each other may be made of different materials that are not weldable to one another.